The research found 70 per cent had never had a mammogram. Uptake was lower outside Auckland and in households with an income below $100,000.

Foundation chief executive Van Henderson said women whose cancer was detected by screening had a 95 per cent chance of surviving the following five years.

"Early diagnosis and treatment have been proven to save lives," said Henderson. "Women need to be proactive about their breast health, and that means getting screened from age 40. If you wait until you find a lump, it might be too late."